A steam turbine rotationally drives a rotor by steam supplied from a boiler. The steam turbine transmits a rotation of the rotor to a generator so as to operate the generator.
A stop valve is provided in a steam supply pipe through which the steam is fed from the boiler to the turbine main body. During a normal operation of the steam turbine, the stop valve is in an open state. Accordingly, the steam is supplied from the boiler to the turbine main body through the steam supply pipe. For example, in a case where any abnormality occurs in the steam turbine, the stop valve closes the steam supply pipe and blocks the supply of the steam from the boiler to the turbine main body.
Patent Document 1 discloses a stop valve which includes a valve main body which has a valve seat, a valve disc which can abut the valve seat, a valve stem in which one end is connected to valve disc, a drive shaft which is connected to the other end of the valve stem, and a drive device which moves the drive shaft forward or backward in a direction in which the valve disc moves close to or away from the valve seat.
In the stop valve disclosed in Patent Document 1, the valve stem and the drive shaft are connected to each other via a connection member. The connection member includes division members facing each other in a state where the valve stem and the drive shaft are interposed therebetween. Each division member includes engagement protruding portions which engage with a valve stem-side engagement recessed portion formed in the valve stem and a drive shaft-side engagement recessed portion formed in the drive shaft. An end portion of the valve stem and an end portion of the drive shaft are interposed between a pair of the division members, and thus, the engagement protruding portions formed in each division member engage with the valve stem-side engagement recessed portion and the drive shaft-side engagement recessed portion. In this state, the pair of division members is integrally connected by a bolt which extends in a direction orthogonal to a direction of a center axis of each of the valve stem and the drive shaft.